Fernox Leak Sealer F4 is used throughout domestic heating systems for sealing small, internal, inaccessible leaks. Leak Sealer F4 works best in warm/hot circulating water and once evenly dispersed will usually be effective within 1 - 24 hours. The sealing efficiency of Leak Sealer F4 has been intentionally limited to prevent blockage of safety devices, pumps, etc.
Internal Leak Sealer
Ideal for reducing pressure loss in sealed systems
Seals most weeps and small inaccessible leaks
Saves time and money on draining down and repairing
Does not cause blockages of pump, air vents etc
Compatible with all metals and materials commonly used in central heating systems